Measurement of theZγ→νν¯γProduction Cross Section and Limits on AnomalousZZγand

V. M. Abazov¹,

B. Abbott²,

M. Abolins³

et al.

Abstract

We present the first observation of the Zgamma --> nunu[over ]gamma process at the Fermilab Tevatron at 5.1 standard deviations significance, based on 3.6 fb;{-1} of integrated luminosity collected with the D0 detector at the Fermilab Tevatron pp[over ] Collider at sqrt[s] = 1.96 TeV. The measured Zgamma production cross section multiplied by the branching fraction of Z --> nunu[over] is 32 +/- 9(stat + syst) +/-2 (lumi) fb for the photon E_{T} > 90 GeV. It is in agreement with the standard model prediction of 39 +/- 4 fb. We set limits on anomalous trilinear Zgammagamma and ZZgamma gauge boson couplings, most of which are the most restrictive to date.

Measurement of the production cross section for $ \mathrm{Z}\gamma \to \nu \overline{\nu}\gamma $ in pp collisions at $ \sqrt{s} = 7 $ TeV and limits on ZZγ and Zγγ triple gauge boson couplings

“…Searches for anomalous ZZγ and Zγγ TGCs have been performed at LEP [7][8][9], the Tevatron [10][11][12], and the Large Hadron Collider (LHC) [13,14]. No evidence has been found; the most stringent limits in pp collisions at √ s = 7 TeV were set by the ATLAS Collaboration [14].…”

Limits on Anomalous Trilinear Gauge Couplings inZγEvents frompp¯Collisions ats=1

“…These measurements use over twice as much data as the previous published CDF result [1] and incorporate looser muon selection requirements. As no significant disagreement is found between the SM prediction and the data, we set limits that are not only far more restrictive than those measured in [1], but are approximately half the magnitude of the previous best published limits [4].…”

“…These results are consistent with standard model predictions. DOI Studies of trilinear couplings between the gauge bosons (W, Z, ) test the standard model (SM) description of gauge sector interactions and provide sensitivity to physics beyond the SM through examination of production rates and kinematics [1][2][3][4][5][6]. In the case of neutral couplings, ZZ and Z vertex interactions vanish at tree level and, while allowed via internal particle loops, are highly suppressed in the SM.…”

“…The resulting allowed ranges for the strength of anomalous couplings are shown in Table II. The values à ¼ 1:2 TeV and à ¼ 1:5 TeV have been chosen to allow direct comparisons with earlier CDF [1] and D0 [4] results, respectively. We see no evidence for anomalous couplings.…”